The SIG-Sauer MPX is a submachine gun produced by SIG-Sauer. First announced in 2013, the weapon is available in several selective fire configurations for military and police use. The SIG MPX is a modular weapon which can be user-configured to fire three calibers: 9x19 mm Luger/Parabellum, .357 SIG or, .40 S&W. It is gas operated, utilizing short-stroke gas piston and rotary bolt locking, firing from a closed bolt for enhanced accuracy and safety. It takes ammunition from proprietary box magazines, made of translucent polymer and holding 10, 20 or 30 rounds. Its layout is partially based on the AR-15 platform.
The MPX features a slightly higher damage model compared to most of the other Personal Defense Weapons with its .40 S&W round, doing 27 damage and dropping off to 13, along with having a high rate of fire at 850 RPM and very tight hipfire spread. The weapon is also very accurate, with fairly low spread values as well as easily controllable recoil; the weapon's primary downside is its slow bullet velocity. With these attributes, the MPX is geared significantly towards close quarters fights, capable of easily dealing with enemies within 12 meters. Past 12.5 meters, though, the weapon's damage begins to fall off, eventually only doing 13 damage at 50 meters.
With its abilities in close quarters, the weapon works well with an Ergo or Vertical Grip and a Laser sight, which will further improve its hipfire accuracy. A Suppressor also functions well with the MPX if the player is outfitting it for close engagements, keeping the player off the minimap and the gun quiet, while the lowered velocity won't make much a difference at these ranges. Conversely, a Heavy Barrel can improve the MPX's performance at longer ranges by decreasing ADS spread, though an Angled or Folding Grip should be used to combat the additional recoil from the barrel. A Stubby or Potato Grip is largely unnecessary for the MPX, as its base spread is very low and manageable.
— In-game description
The MPX is a purchasable Submachine gun featured in Battlefield Hardline for the Law Enforcement Mechanic. It is capable of reloading significantly faster than most other SMGs in-game. The MPX also has moderate recoil and hip-fire control. Its relatively low spread and recoil makes it suitable for medium range engagements.
- The MPX was first discovered in the game files after a patch for the Community Test Environment on PC.
- The trademarks on the left side of the gun read "CHD COMBAT PDWX" in a spoof of SIG Sauer's logo. This seems to suggest that the MPX was originally going to be called the PDWX, but was given its real name in-game instead.
- The MPX, when first released had a 25+1 round magazine. This changed during the Spring Patch, when it gained 5 more rounds.
- On occasion, the MPX suffers from a reload bug in which the magazine disappears and nothing is reloaded into the gun, nor does it make the sounds associated with inserting the magazine, though the soldier makes the hand motions of doing so. This does not affect the gun performance in any way, and is most likely to occur after being revived or when the animation is interrupted before inserting the magazine.
- The MPX is the most recently developed firearm in Battlefield 4, with the weapon being released after the game itself.
- The MPX's singleplayer appearance in 2012 is anachronistic, as it was not designed until 2013.
- The menu icon shows the MPX with a light grey color, but it has a black metal color in-game.